During the course of a surgical procedure, a surgical tool may undergo relatively high mechanical loads on various parts of the tool. Such mechanical loads may be rotational torque loads and/or axial loads. A tool having a surgical implement on one end that is inserted in a surgical site may require high torque forces in order to rotate the implement against hard tissue. If a torque force required to rotate the surgical implement is greater than the tool can withstand, the tool may be damaged and/or become inoperable. This may require the tool operator to remove the tool from the surgical site in order to repair the tool or to retrieve a replacement tool to continue with the procedure. Moreover, if a surgical tool is damaged or breaks while inserted in a patient, the patient may be injured.
Some conventional surgical tools have been designed to break in a predetermined position when torque forces greater than the tool can withstand are applied. For example, a tool may include a groove at a particular location such that a predetermined torque causes the tool to break at the groove. The predetermined torque breaking point may require less torque force to break that portion of the tool than would cause other portions of the tool to break. In this way, the tool may break prior to breakage in a more undesirable portion of the tool that may cause injury to a patient.
A disadvantage of such a conventional design is that when the tool breaks, the surgeon must stop the procedure to repair or replace the tool. Another disadvantage is that once the tool breaks, it may be un-repairable and thus require replacement, which can be costly.
A tool having a surgical implement on one end that is inserted in a surgical site may require high axial forces in order to manipulate the implement in certain environments. In a surgical device having a handle and a lever system, a significant axial load can be generated on the connections and attachments of the device. For example, when a curette tip attached to the distal end of a surgical device shaft is inserted into hard bone, articulation of the curette tip about a pivot point to an angle away from the shaft of the device can be restricted by the bone. As increasing axial load is placed on the device, the axial load can exceed the strength of the connection of the curette tip to the device and/or the pivot point. As a result, the surgical curette device can become non-functional and/or damaged. In addition, in surgical sites comprising hard tissue, the curette tip may be able to be moved away from the shaft only in small increments. Such a process may involve repeated stopping of the procedure, such as bone scraping, in order to readjust the position of the lever relative to the handle to change the axial load and correspondingly the angle of the curette tip relative to the axis of the shaft.
Thus, it is desirable to provide a surgical device that avoids being damaged and/or becoming inoperable during use, particularly due to high torque and/or axial loads placed on the device.
Conventional surgical devices often have undetachable components, which are thus not interchangeable. For example, a surgical tool such as a curette can be configured with one shaft and curette assembled to a handle and cannot be detached. Some surgical procedures may require manipulation of a surgical implement such as a curette attached to the end of a shaft at various locations within a surgical site. For this purpose, the length, flexibility, or other characteristics of the shaft may need to be different for accessing different levels of the surgical site. In some procedures, different sizes, shapes, or other characteristics of the curette tip may be desired for scraping different tissues. Conventional surgical devices with undetachable components require the surgeon to use entirely separate multiple devices to have such procedural flexibility. Providing entirely separate multiple surgical tools for a single surgical procedure can be costly. Thus, it may be desirable to provide a surgical device having interchangeable components.